изрядно – English translation

a good bit; a nice bit; passably; pretty well (Anglophile); rather (Anglophile); plenty; quite a lot (Alex_Odeychuk); amply (The earl was amply rewarded for this service to the king. ART Vancouver); fairly (Anglophile); decently; respectably

Игорь Миг

more than a few; aggressively

amer.

as all get out (He was as tired as all get out. VLZ_58)

amer., slang

all get out (точный перевод зависит от контекста)

cliche.

a fair amount (You might have caught on that it rains a fair amount in Vancouver. It's important to have the essentials as you go about your day-to-day and explorations in the city. (Twitter) ART Vancouver)

Gruzovik, inf.

quite a; fair; handsome; considerably; so-so; perfectly; tolerably; excellently

inf.

extremely well; smartish

Makarov.

in a great measure; in a large measure

slang

pretty; sitting pretty

изрядный adj.

gen.